独立圆盘耙单体排列参数对秸秆堵塞影响研究

为对秸秆覆盖混埋还田耕整地技术模式进行深入研究,需要研发配套圆盘耙联合整地机具,机具研发过程中首先要解决受秸秆影响的堵塞问题。通过进行影响因素的单因素试验和3因素3水平正交试验,探索独立连接圆盘耙单体排列参数对秸秆堵塞问题的影响规律。通过单因素试验确定对应机具通过性评分为3分的三个因素临界值:耙片间距为275 mm,横梁间距为900 mm,错位间距取值全部满足试验要求。正交试验极差分析结果表明:耙片排列参数对机具堵塞影响主次顺序为耙片间距B,横梁间距L,错位间距S;机具通过性的较优组合为耙片间距325 mm,横梁间距1 100 mm,错位间距0 mm。正交试验方差分析结果表明机具排列参数耙片间距和横梁间距对机具堵塞影响显著,错位间距对机具堵塞影响不显著。正交试验回归分析结果得到拟合度较高的机具通过性回归方程:T=0.833B+0.667L。本文试验结果为圆盘耙联合整地机的开发与设计提供数据参考。     

基于正交设计的施用硫磺、控水灌溉和施肥对蓝莓生长的影响

旨在优化高寒地区蓝莓栽培模式,利用正交试验研究了施用硫磺、控水和施肥3个因素对大兴安岭地区蓝莓品种‘美登’植株生长的影响。结果表明:3个因素正交处理对蓝莓生长指标的影响程度较大,不同处理之间各生长参数均存在较大的变异幅度,3个因素之间存在明显的互作效应,并且拮抗效应较小。极差分析结果表明,对蓝莓株高、冠幅和枝条长度影响最大的因素为土壤相对含水率,而对枝条粗度影响最大的因素为施肥。3个因素互作下均表现为各因素的3水平或4水平蓝莓生长性状最优,结合各生长参数的变化结果,建议大兴安岭地区蓝莓品种‘美登’施用硫磺量为70~80 g/m2,施硫酸钾复合肥7.5~10 g/株,土壤相对含水率维持在45%~60%。     

不同林龄枫香子代性状变异与家系选择

对布设在安徽祁门县的首批84个枫香子代测定林，分析比较了9年生与3年生两个不同林龄胸径、树高性状的遗传力和遗传增益等参数，并开展了优良家系选择。结果表明不同时期入选的家系名称、数量及名次出现较大差异，大部分家系胸径、树高性状的家系遗传力、单株遗传力及遗传增益等参数估值，表现为随林龄增大而降低。研究结果为枫香良种选育的适宜林龄提供了参考依据。     

Critical comparison of the vanadomolybdate and the molybdenum blue methods for the analysis of phosphate in plant sap

Abstract

The performance of the vanodomolybdate and molybdenum blue methods for the routine determination of phosphate in plant sap were compared in order to assess their suitability for the detection of P deficiency at an early stage of plant growth. The molybdenum blue method was ca 10 times more sensitive than the vanadomolybdate one and required less sap to give a successful test. Recoveries of phosphate added to both sap and solution samples were close to 100% with both methods. The methods were in good agreement over a wide range of phosphate concentrations using sap samples from all leaves during the early stages of P deficiency, but increases in sap background colour caused the vanadomolybdate method to overestimate phosphate concentrations as the deficiency became more acute. Measurements on solutions of similar absorbance showed that the vanadomolybdate method was not significantly more variable than the molybdenum blue method but tended to overestimate phosphate concentration when very small volumes of sap were available. It was concluded that the molybdenum blue method was the most reliable for routine measurements of phosphate in plant sap.     

品种区域试验主要决选指标及其参数的研究——Ⅳ.参数数量分类与区试品种分类

本文根据变量理论分布对区试中b值及CV值参数的数量分类,提出了适于目前普及推广的查表计算法。在此基础上,对区试品种提出了按主要生产性能指标以量定性的评定分类体系。从而推出可排除主观随意性干扰、较为完整严密的区试汇总模式,并以范例作了运用说明。     

木薯渣与甜菜颗粒粕组合效应对奶牛瘤胃发酵特性的影响

本试验旨在通过体外产气法研究木薯渣与甜菜颗粒粕组合用作泌乳中后期奶牛饲料的可行性及适宜组合比例。试验设计7个处理:木薯渣分别以0%(对照组)、5%、10%、15%、20%、25%和30%与甜菜颗粒粕(风干物质基础)组合,使用AGRS-Ⅲ型微生物发酵产气系统进行体外瘤胃微生物发酵试验,监测体外培养3、6、12、24、48h后的发酵液pH、氨态氮(NH3-N)、微生物蛋白(MCP)含量和体外培养48h后干物质消失率(IVDMD)、累积产气量(GP)及挥发性脂肪酸(VFA)含量等指标。结果表明:体外培养48 h后,GP和底物的最大降解率(RmaxS)随木薯渣占比增加呈线性或二次增加(P<0.05);发酵液各VFA和TVFA含量均随木薯渣占比增加呈线性或二次降低(P<0.05);根据多项组合效应值,以0%组为对照时,5%组和10%组表现为正组合效应,其余组合均表现为负组合效应。在本试验条件下,当木薯渣与甜菜颗粒粕组合使用,且木薯渣为5%~10%较为适宜,但此结果仍需奶牛饲养试验进一步验证。     

Pathological analysis of batch safety testing of veterinary vaccines using small laboratory animals

Batch safety tests (BSTs) of veterinary vaccines are conducted using small laboratory animals to assure the safety of vaccines according to several criteria, including clinical signs and change in body weight. Although the latter is used as an evaluation index in BSTs, there have been no reports on the internal changes that affect body weight during the test period. Therefore, we analyzed BST via pathological examination of the tested animals. Here, BSTs were performed for 176 batches using mice and 126 batches using of guinea pigs. Most of the gross findings could be classified into four lesion types (nodules, adhesions, ascites, no apparent signs), with only one vaccine inducing lesions that could not be classified into any of these four types. Histopathological examination revealed that the reactions caused by BST were pyogenic and/or granulomatous inflammation. Nodular or adhesive lesions comprised more severe pyogenic granulomatous inflammation than ascites or cases with no apparent gross lesions. These nodular or adhesive lesions were more frequently induced by vaccines that contained an adjuvant than by vaccines that did not contain an adjuvant. The cases with “exceptional” gross findings histologically presented severe necrosis of the hematopoietic system. Additional testing showed that these “exceptional” lesions were induced when a specific type of light liquid paraffin was injected along with other vaccine additives. Our results show that body weight loss and/or lesions during BST were induced by proinflammatory properties of the tested vaccines and that BST is a sensitive method for detecting unexpected effects of vaccine components.     

Carrier rate of the c.235G>C mutation in the bovine isoleucyl-tRNA synthetase (IARS) gene of Japanese Black cows at Kagoshima prefecture, Japan,and analysis of the metabolic profiling and reproductive performance of heterozygous cows

Bovine isoleucyl-tRNA synthetase (IARS) disorder, a major cause of weak calf syndrome, is caused by a homozygous missense (c.235G>C) mutation in the bovine IARS gene of Japanese Black (JB) cattle, which was identified in 2013. However, the extent to which the carrier rate has changed at Kagoshima prefecture, Japan, and whether the carrier status is associated with any clinical or reproductive problems, have yet to be ascertained. In this study, using a real-time polymerase chain reaction-based genotyping assay, we determined the carrier rate in a regional JB cow population at Kagoshima prefecture. Comparative analyses were performed on the metabolic profile test (MPT) results and reproductive performance data obtained for heterozygous carrier and homozygous wild-type cows. In 2009 and 2018, DNA samples were collected from 130 and 462 clinically healthy JB cows, respectively, in Kagoshima prefecture. MPT results and reproductive performance data were evaluated for 62 cows, comprising four heterozygous carriers and 58 wild-type cows. Genotyping revealed that the carrier rate was 6.9% in 2009 and 1.5% in 2018, the difference of which was statistically significant (P<0.005). There were no statistically significant differences between the carrier and wild-type cows with respect to either MPT results or reproductive performance, indicating that the carrier cows have necessary IARS activity to maintain minimal health and reproductive potential.     

Influence of acute exposure to a low dose of systemic insecticide fipronil on locomotor activity and emotional behavior in adult male mice

Fipronil (FPN) is a systemic insecticide that antagonizes the gamma-aminobutyric acid type A (GABA_A) receptors in insects. Recently, adverse effects of FPN on mammals have been reported, but most of those were caused by high doses of FPN and additives in the products. We investigated the effects of low-dose pure FPN on the emotional behavior of mice. Nine-week-old male mice conducted behavioral tests 24 hr after FPN administration by gavage at doses of 0.05 or 5 mg/kg based on the no-observed-effect level (NOEL), showed a significant increase in locomotor activity and dose-dependent responses on the time they spent in the central zone in the open field test. Pure FPN below the NOEL dose may affect the emotional behavior of mice.